Purification of tin



JEROME JOHN COLLINS, or iSOUTHPOR'I, ENGLAND.

PURIFICATlION or TIN.

No Drawing.

T 0 all whom cit-mag] concern:

Be it known that I, JEROME J oIIN Connms, a subject of the King of GreatBritain and Ireland, and resident of 9 Leicester Street,"

Southport, in the county of Lancaster, England, have invented certain new and useful Improvements Relating to the Purification o'f Tin, of which the following is a specification. V

This invention relates to the purification of tin.

My invention comprises the production:

from the impure tin of stannous chloride by the action of stannic chloride on the 1mpure metal in the presence of an excess of tin, the stannous chloride being dehydrated and when in a molten condition, electrolyzed whereby pure metallic tin is obtained and is drawn off from the electrolyzer, the chlorine evolved attacking the stannous chloride at the anode and producing stannic chloride which maybe used in the process for obtaining stannousf chloride from impure tin. p In one convenlent application of my invention, a solution of stannous chloride is obtained from the impure metal by subjecting the latter to the action of; stannic chloride, thestannic chloride'dissolving the tin there being always an excess of tin in the reaction vessel.

' precipitation of the chlorides of arsenic and antimony as insoluble oxychlorides and also the precipitationas metal'of any bismuth present. Lead chloride-which is dissolved by the hot liquid precipitates when the latter is cooled. a

- The stannous chloride obtainedasaforesaid is heated in the presence of metallic tin under a slight vacuum and out of contact with air, to drive off the -water of crystallization and the anhydrous body is I heated in an ele'ctrolyzer to about 260 degrees centigrade'at which temperature. ity is molten, and an electric current passed there- Or the cathode may be made of cast iron and may I be conveniently formed by making the electrolyzer itself of cast iron. tin may be used as the cathode.

St nnous chloride forms the electrolyte,

The excess of tin causes the obtained, as set forth; through between the anode and cathode, both of which maybe made of carbon.

or the molten The molten Specification of letters latent. t t d, APR 5 Application filed April 6, 1921. Serial 1 10. 459,121, i i i i The anodes may be cooled bywater jacketing or otherwise; @thebath is maintained at the required temperature to keep the electrolyte in the'molten or; fused state, by a. sur

rounding hot'fiue or in any other convenient manner. I

The passage of the electric current through theelectrolyte causes the decomposition of the latter, molten tin being given off at the cathode and chlorine at the anode.' V

.The'chlorine attaoksthe stannous chloride at the anode forming stannicchloride which boils off as a gasjand may be'recovered in a separate vessel .by'condensation or absorption. The reaction between the stannic chloride and chlorine which takes place at V the anode being exothermic, the heat evolved assists in maintaining the stannous chloride .in a molten or fuse'd condition.

in which the stannous chloride is dehydrated may also communicate with the vessel in which the gaseous stannic chloride is con densed or absorbed). A weak solution of venient absorbent for the gas. The stannic chloride, thus obtaincdcan be utilized, in the process of purifying tin, for dissolving the tin from the impure metal toyield the deis lower than the fusiontemperature'of stannous chloride. 1 p

Having now-described my invention what (The vessel '75 stannic or stannous chloride forms a coni I claim as new and desire, to secure by Letters 1. The process of purifying tin,"cons'isting in producing pure stannous chloride from the impure metal by the action .of stannic chloride" on' the latter in the presence of an excess of tin, and dehydrating, fusing'and electrolyzing the stannous chloride whereby pure metallic tin and stannlc chloride are 2. The process of purifying tin as claimed in claim 1, in which thestannous chloride is dehydrated in the presence of metallic tin and out of contact with air, as set forth. I

In testimony-whereof I have signed my v name to'this specification.

JEROME JOHN COLLINS.

80 sired stannouschloride in the presence of an. excess of tin. r The. liberated molten tin is run off from the electrolyzer. The melting point of tin 

